#include <iostream>
#include <cstdio>
#include <cmath>
using namespace std;
int main(int argc, char** argv) {
int a,b,c;
cin>>a,b;
c=jc(a,b);
cout<<c;
return 0;
}
int jc(int m,int n){
int z;
z=mc(m)/(mc(n)*mc(m-n));
return(z);
}
int mc(int d){
int x=1;
for(int i=1;i<=d;i++){
x*=i;
}
return(x);
}